The type of hot water diving suit shown and described herein is manufactured by Diving Unlimited International of San Diego, California, in both closed circuit and non-return or open circuit configurations. The suit is basically loose fitting and contains water distributing tubes to conduct hot water to all parts of a divers body inside the suit. Hot water is supplied from a source on the surface through a hose connected to the suit, along with the breathing air supply, distribution of the hot water being controlled by a diver operated manifold valve on the suit. In the non-return type of suit, the hot water is allowed to leak out at a controlled rate, at which the available supply can maintain a comfortable temperature in the suit. This type of suit enables a diver to work for extended periods at great depths, of 600 to 1000 feet or more, in near freezing water.
A typical example of such use is in the installation of valves and connections for oil wells on the ocean floor. For deep diving operations of this type a pressurized diving bell or similar refuge is situated near the work area, so that the diver need not depressurize between work periods.
If the hot water supply is interrupted for any reason, the diver must reach a heated refuge very quickly, or the exposure to the cold water can be fatal. About five minutes is the limit at which a diver can expect to survive without heat in near freezing water at great depths. Since the cold exterior water must extract all the heat from the hot water in the suit before starting to reduce body heat, it is essential to retain as much hot water in the suit as possible.
When the suit is equipped with multiple outlet valves for exhausting the hot water, all valves must be closed quickly in an emergency. With the valves open, any movement of the diver which distorts the suit causes a pumping action through the valves, by which hot water is forced out and cold water is drawn in. It is therefore essential for the diver's safety to provide rapid and positive means for sealing the suit, to retain the hot water and prevent intake of cold water.